Canadian wildfires are the cause of an air quality alert that’s in effect for the tri-state area, according to health officials. New York City’s air quality index is at 118 on Tuesday, AirNow’s tracker indicates.

Hazy skies descend over the New York City area again on Tuesday, re-upping some air quality alerts related to Canadian wildfire smoke. As of 9 a.m., the air quality index was 118, which is considered unhealthy for sensitive groups.

Smoke from Canadian wildfires is causing air quality concerns for millions of Americans in the Midwest and Northeast. Air quality alerts were in effect Tuesday in several states, including Wisconsin,